1. Field of the Invention
This invention relates generally to pressure vessels, such as pressurized gas canisters and compressed gas cylinders, and, more particularly, to a head ring assembly for protecting the valving of pressure vessels.
2. Description of the Related Art
The Air Transport Association (xe2x80x9cATAxe2x80x9d) and the International Air Transport Association (xe2x80x9cIATAxe2x80x9d) have recently released specifications affecting the design of airline shipping containers. Specifications ATA-300 and IATA-200 establish the airline industry""s standards for acceptable packaging of shipping containers used in air transport and address such issues as proper packaging design, marking, and inspection/testing. These specifications ensure that materials, such as pressurized cylinders containing oxygen and other fluids, are adequately protected during handling and transport. For example, these specifications require that gas cylinders have valve protection head rings to protect the valves from damage or inadvertent opening during transport. Further requirements ensure the integrity of packaging and valving after repeated exposure to extreme temperatures, harsh chemicals, and vibration. Thus, these specifications ensure the safe handling and transport of compressed fluids and other materials.
At least one head ring design has previously been used to protect the valving associated with a pressure vessel. This previous head ring was designed to protect the regulator, flow adjuster, and content gauge during handling and transport of the pressure vessel. The design has spaced-apart concentric rings that surround the valving, protecting the valving. Aviation Mobility, for example, manufactured such a head ring (Aviation Mobility, a division of Access Management Group, 201 South Tryon Street, Suite 1210, Charlotte, N.C. 28202, tel. 704-525-7005, www.accessmg.com).
Previous head ring designs, however, often incurred damage in the field. While previous head ring designs protected the valving to some extent, the head ring itself often deformed from normal use. Welds, for example, failed from impacts. Rings were damaged because of these failed welds. These weld failures shortened the expected life of each head ring and created premature repair costs.
Other problems with these previous head ring designs involved the fastening mechanism. Prior head rings used a clamping system to attach the head ring to the pressurized cylinder. A U-bolt, for example, clamped the head ring to the cylinder. This U-bolt clamping system, however, could not maintain proper orientation between the head ring and the valving. The U-bolt clamp permits the head ring to rotate and expose the valving. The U-bolt clamp also has exposed threads, and these exposed threads were easily damaged during handling. These damaged threads make the U-bolt difficult to remove. The U-bolt clamping system is also labor intensive and requires an intricate field operation.
Prior head ring designs also had compatibility problems. While there are two leading manufacturers of light-weight gas cylinders, there are slight dimensional differences between each manufacturer""s cylinder design. These dimensional differences are acute in the neck region of the cylinder. Previous head ring designs were not compatible with both manufacturers. One head ring design was required for one manufacturer, while another head ring design was required for the other manufacturer. This compatibility problem increased the cost of the head ring and created confusion and mismatch.
There is, accordingly, a need in the art for a head ring design that is robust, a head ring design that is easily attached and properly oriented to a gas cylinder, a head ring design that is compatible with multiple cylinder configurations, and a head ring design that is always cost effective.
The aforementioned problems are minimized by the present invention. A head ring protects the valving assembly, or regulator, flow adjuster, and content gauge, commonly attached to pressure vessels, such as conventional pressurized gas cylinders. The head ring includes a base securable to the dispensing end of the pressure vessel. A plurality of posts are distributed about a perimeter of the base, each of the posts extending vertically upward from about the base to beyond the valving assembly. Each of the posts has a first end and a second end. A collar is secured to a portion of the perimeter of the base, and the collar extends vertically downward from the perimeter of the base. The collar includes a radially-extending flange at each end. A first ring horizontally extends from the posts and is secured adjacent to the first end of the posts. A second ring horizontally extends from the posts and is secured adjacent to the second end of the posts. The first ring and the second ring are radially positioned outward of the regulator, the flow adjuster, and the content gauge. A gauge protection plate extends vertically downward from the first ring. The gauge protection plate includes an interior wall defining a plate opening. The plate opening is sized to allow visual access to the content gauge. The head ring protects the valving assembly during handling and transport of the pressure vessel. The head ring assembly may also comprise part of a pressure vessel assembly or a package assembly for protecting the pressure vessel, the package assembly including an outer pack made from a durable material defining a bag sized to surround the pressure vessel.